Safety Switching Device For Fail-Safely Disconnecting An Electrical Load

A safety switching device for fail-safely disconnecting an electrical load, comprising:

• an input part for receiving at least one safety-relevant input signal,
• a logic part for processing the at least one safety-relevant input signal, and
• an output part which comprises a relay coil and a first relay contact, a second relay contact, a third relay contact, and a fourth relay contact,
• wherein the first and the second relay contacts are arranged electrically in series with one another,
• wherein the third and the fourth relay contacts are arranged electrically in series with one another,
• wherein the first and the third relay contacts are mechanically coupled to each other so as to form a first group of positively driven relay contacts,
• wherein the second and the fourth relay contacts are mechanically coupled to each other so as to form a second group of positively driven relay contacts,
• wherein the first and the third relay contacts can move mechanically separately from the second and the fourth relay contacts,
• wherein the logic part redundantly controls the first group of positively driven relay contacts and the second group of positively driven relay contacts in order to selectively allow, or to interrupt in a fail-safe manner, a current flow to the electrical load, in response to the at least one safety-relevant input signal, and
• wherein the relay coil is electromagnetically coupled to the first group and to the second group of positively driven relay contacts in such a manner that the logic part can control the first relay contact, the second relay contact, the third relay contact, and the fourth relay contact together via a single relay coil.